connection between electricity and magnetism. 41 The trajectory followed by Chinese science is therefore an obvious one: given their understanding of the properties of magnetized needles, they expanded this knowledge into obvious directions (above all the compass), but they failed to make the less probable leaps made by Oersted and Henry. In the absence of Western influence, China would probably not have gone in that direction in historical times.

The issue of steampower is more complex. Pomeranz has argued that the Chinese had the “basics” for the steam engine.42 The minimum epistemic base for the use of atmospheric pressure in order to convert heat into work are the notion of atmospheric pressure and the understanding of the physical changes in water under different temperatures. In addition, it required the workmanship and materials that could create a pump capable of producing a vacuum inside a cylinder or a globe. Knowledge of the atmosphere, the understanding of water-condensation, and the ability to construct advanced pumps can surely be found in China, and if all that was required to make a steam engine was the knowledge of physics of, say, a Denis Papin or a John Smeaton, it is indeed likely that in the absence of the West, the Chinese would have stumbled upon something like it. But it is telling that the earliest reference to the epistemic base of steam power in China dates from the Han period and predate Newcomen by almost two millennia, and yet nothing happened in China that we know of with certainty.43 In the West, by contrast, models of a working steam engine appeared within about half a century after Torricelli’s demonstration of atmospheric pressure and Pascal’s Traité de l'équilibre des liqueurs et de la pesanteur de la masse de l'air. Furthermore, Needham points out that the mechanical bellows described by Wang-Chên in 1313 has the structure of a reciprocating steam engine “in reverse” incorporating double-action and a transmission mechanism similar to Watt’s famous sun-and-planets gears.44 However, the essence of the steam engine is the conversion of heat into work, a problem cracked before Watt’s ideas of double-acting. Thus the transformation of Newcomen’s clumsy and noisy pump to Watt’s industrial source of power may well have had Oriental antecedents (whether Watt was aware of them or not), but the concept of an engine was novel. Needham concedes that in this regard Europe

43In his famous essay on the topic, Needham, “The Pre-natal History of the Steam Engine” published in Clerks and Craftsmen p. 145 tells of a document from the 2nd century BC in which a Chinese author explains that “to make a sound like thunder, put boiling water in a vessel and sink it into a well. It will make a noise that can be heard several dozen miles away,” an experiment that anticipated Magdeburgian effects.